/**
 * @file InteractiveRebase.tsx
 * @description Interactive rebase as a list (JetBrains' "Interactively Rebase
 * from Here"): the branch's commits since a base — by default the ones no
 * remote has yet, oldest first — each with Pick / Reword / Squash / Fixup /
 * Drop, moved up and down, a new message for a reword or a squash. Before it
 * runs it says what it rewrites ("This rewrites 4 commits; 2 are already
 * pushed, so a force-push will be needed") and pushed commits need an explicit
 * tick; Start is a two-click (`useArmed`). The server builds the todo and runs
 * `git rebase -i` with no editor; a clean run stays open with **Undo**.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

import { useEffect, useState } from "react";
import { useTranslation } from "react-i18next";
import { ArrowDown, ArrowUp } from "lucide-react";
import type { GitTarget } from "../../../lib/api";
import {
  errText,
  gitRewrite,
  type InteractivePlan,
  type PlanCommit,
  type RewriteResult,
  type TodoAction,
} from "../../../lib/gitRewrite";
import { toast } from "../../../lib/toast";
import { useArmed } from "../../../hooks/useArmed";
import { BTN, BTN_DANGER, ErrorLine, GitModal, Warn } from "./GitModal";
import { RewriteDone } from "./RewriteDone";
import { blockedReason } from "./RebaseDialog";

const ACTIONS: TodoAction[] = ["pick", "reword", "squash", "fixup", "drop"];

interface Row {
  commit: PlanCommit;
  action: TodoAction;
  message: string;
}

/** Why the list cannot run as it stands, or null. */
export function todoProblem(rows: Row[]): "first" | "allDropped" | "unchanged" | "reword" | null {
  const kept = rows.filter((r) => r.action !== "drop");
  if (!kept.length) return "allDropped";
  if (kept[0]!.action === "squash" || kept[0]!.action === "fixup") return "first";
  if (rows.some((r) => r.action === "reword" && !r.message.trim())) return "reword";
  return null;
}

export function InteractiveRebase({
  target,
  base,
  onClose,
  onChanged,
}: {
  target: GitTarget;
  /** Rewrite the commits after this one; absent = the unpushed ones. */
  base?: string;
  onClose: () => void;
  onChanged: () => void;
}) {
  const { t } = useTranslation(["gitTools"]);
  const [plan, setPlan] = useState<InteractivePlan | null>(null);
  const [rows, setRows] = useState<Row[]>([]);
  const [force, setForce] = useState(false);
  const [busy, setBusy] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [result, setResult] = useState<RewriteResult | null>(null);
  const { isArmed, arm, disarm } = useArmed();
  const key = JSON.stringify(target);

  useEffect(() => {
    let live = true;
    gitRewrite
      .planInteractive(target, base)
      .then((p) => {
        if (!live) return;
        setPlan(p);
        setRows(p.commits.map((c) => ({ commit: c, action: "pick", message: c.message })));
      })
      .catch((e) => live && setError(errText(e)));
    return () => {
      live = false;
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [key, base]);

  const set = (i: number, patch: Partial<Row>) =>
    setRows((prev) => prev.map((r, n) => (n === i ? { ...r, ...patch } : r)));
  const move = (i: number, step: number) =>
    setRows((prev) => {
      const j = i + step;
      if (j < 0 || j >= prev.length) return prev;
      const next = [...prev];
      [next[i], next[j]] = [next[j]!, next[i]!];
      return next;
    });

  const blocked = plan ? blockedReason(t, plan) : null;
  const problem = todoProblem(rows);
  const unchanged =
    !!plan && rows.every((r, i) => r.action === "pick" && r.commit.sha === plan.commits[i]?.sha);
  const pushed = plan?.pushed ?? 0;

  const run = async () => {
    if (!plan) return;
    if (!isArmed("run")) return arm("run");
    disarm();
    setBusy(true);
    setError(null);
    try {
      const r = await gitRewrite.run(target, "rebase-interactive", {
        head: plan.head,
        ...(base ? { base: plan.base } : {}),
        confirm: true,
        ...(pushed ? { force: true } : {}),
        todo: rows.map((row) => ({
          sha: row.commit.sha,
          action: row.action,
          ...((row.action === "reword" || row.action === "squash") &&
          row.message.trim() &&
          row.message.trim() !== row.commit.message
            ? { message: row.message }
            : row.action === "reword"
              ? { message: row.message }
              : {}),
        })),
      });
      onChanged();
      if (r.conflicts?.length || r.stopped) {
        toast.error(t("rebase.stopped", { count: r.conflicts?.length ?? 0 }));
        onClose();
        return;
      }
      toast.success(t("interactive.done"));
      setResult(r);
    } catch (e) {
      setError(errText(e));
    } finally {
      setBusy(false);
    }
  };

  return (
    <GitModal
      title={t("interactive.title")}
      onClose={onClose}
      testId="interactive-rebase"
      footer={
        result ? (
          <button type="button" className={BTN} onClick={onClose}>
            {t("close")}
          </button>
        ) : (
          <>
            <button type="button" className={BTN} onClick={onClose}>
              {t("cancel")}
            </button>
            <button
              type="button"
              data-testid="interactive-run"
              className={BTN_DANGER}
              disabled={
                busy || !plan || !!blocked || !!problem || unchanged || (pushed > 0 && !force)
              }
              onClick={() => void run()}
            >
              {isArmed("run") ? t("interactive.runConfirm") : t("interactive.run")}
            </button>
          </>
        )
      }
    >
      {result ? (
        <RewriteDone target={target} result={result} onChanged={onChanged} onUndone={onClose} />
      ) : !plan ? (
        error ? (
          <ErrorLine error={error} />
        ) : (
          <p className="text-fg-muted">{t("loading")}</p>
        )
      ) : (
        <>
          <p className="mb-1.5 text-[11px] text-fg-muted">{t("interactive.explain")}</p>
          {blocked && <Warn>{blocked}</Warn>}
          {plan.merges && <Warn>{t("interactive.merges")}</Warn>}
          {!rows.length ? (
            <p data-testid="interactive-empty">{t("interactive.nothing")}</p>
          ) : (
            <>
              <Warn testId="interactive-summary">
                {pushed
                  ? t("rewritesPushed", { count: rows.length, pushed })
                  : t("rewrites", { count: rows.length })}
                {pushed > 0 && (
                  <label className="mt-1 flex items-center gap-1.5">
                    <input
                      type="checkbox"
                      data-testid="interactive-force"
                      checked={force}
                      onChange={(e) => setForce(e.target.checked)}
                    />
                    {t("forceAck")}
                  </label>
                )}
              </Warn>
              <ol data-testid="interactive-list" className="space-y-1">
                {rows.map((r, i) => (
                  <li
                    key={r.commit.sha}
                    data-testid="interactive-row"
                    className={`rounded border border-border-light p-1.5 ${
                      r.action === "drop" ? "opacity-50" : ""
                    }`}
                  >
                    <div className="flex flex-wrap items-center gap-1.5">
                      <select
                        aria-label={t("interactive.action", { short: r.commit.short })}
                        data-testid="interactive-action"
                        value={r.action}
                        onChange={(e) => set(i, { action: e.target.value as TodoAction })}
                        className="input py-0.5 text-[11px]"
                      >
                        {ACTIONS.map((a) => (
                          <option key={a} value={a}>
                            {t(`interactive.actions.${a}`)}
                          </option>
                        ))}
                      </select>
                      <span className="shrink-0 font-mono text-[11px] text-fg-muted">
                        {r.commit.short}
                      </span>
                      <span
                        className={`min-w-0 flex-1 truncate text-[11px] text-fg-primary ${
                          r.action === "drop" ? "line-through" : ""
                        }`}
                        title={r.commit.subject}
                      >
                        {r.commit.subject}
                      </span>
                      {r.commit.pushed && (
                        <span className="shrink-0 text-[10px] text-status-warning">
                          {t("pushed")}
                        </span>
                      )}
                      <button
                        type="button"
                        className={BTN}
                        aria-label={t("interactive.up")}
                        disabled={i === 0}
                        onClick={() => move(i, -1)}
                      >
                        <ArrowUp className="h-3 w-3" />
                      </button>
                      <button
                        type="button"
                        className={BTN}
                        aria-label={t("interactive.down")}
                        disabled={i === rows.length - 1}
                        onClick={() => move(i, 1)}
                      >
                        <ArrowDown className="h-3 w-3" />
                      </button>
                    </div>
                    {(r.action === "reword" || r.action === "squash") && (
                      <textarea
                        data-testid="interactive-message"
                        aria-label={t("interactive.message")}
                        value={r.message}
                        rows={3}
                        onChange={(e) => set(i, { message: e.target.value })}
                        placeholder={
                          r.action === "squash" ? t("interactive.squashHint") : undefined
                        }
                        className="input mt-1 w-full font-mono text-[11px]"
                      />
                    )}
                  </li>
                ))}
              </ol>
              {problem && (
                <p
                  data-testid="interactive-problem"
                  className="mt-1 text-[11px] text-status-danger"
                >
                  {t(`interactive.problem.${problem}`)}
                </p>
              )}
            </>
          )}
          <ErrorLine error={error} />
        </>
      )}
    </GitModal>
  );
}